The present invention relates to an internal combustion engine air-fuel mixture supply apparatus for controlling air and fuel supplied to an internal combustion engine.
A so-called sequential injection system is employed in conventionally proposed fuel injection apparatuses. This system is well known as disclosed, for example, in Japanese Patent Unexamined Publication No. JP-A-63-314335.
The sequential injection system is arranged to inject fuel successively just before air-intake strokes of the respective cylinders.
In this case, the quantity of fuel to be injected is determined fundamentally corresponding to the output of an air flow meter provided in a downstream side of an air cleaner.
The air flow meter and each cylinder are connected to each other through an air-intake passage. Accordingly, the quantity of air sucked into each cylinder and the quantity of air metered by the air flow meter at the same point of time are different from each other.
In short, the output of the air flow meter merely exhibits the past air quantity.
Accordingly, the fuel quantity determined based on the output of the air flow meter at a certain point of time has no relation to the quantity of suction air taken into the cylinder at that certain point of time.
Accordingly, the concentration of the air-fuel mixture in the cylinder cannot be determined exactly. There arises a problem in that irregular combustion and fluctuations in rotation occur.